In the Replacement Metal Gate (RMG) process, oxygen ingress during high temperature processing is a common issue causing threshold voltage (Vt) to roll up in n-type FETs (NFETs) and roll down in p-type FETs (PFETs). It is also well known that high-K metal oxides (dielectric constant higher than SiO2) have ionic bonds and tend to transport oxygen via oxygen vacancies when in contact with a deposited oxide material and subjected to a high temperature annealing process. In the state-of-the-art RMG flow, the high-K is in contact with deposited films in the middle-of-the-line (MOL), and could be causing the short-channel Vt shift observed in RMG devices.